EIC Workshop 3/17/14 MEIC Project at Jefferson Lab Fanglei Lin For JLabs MEIC Study Group EIC workshop, Jefferson Lab March 17, 2014 EIC Workshop 3/17/14 MEIC Study Group 2 EIC Workshop 3/17/14 Introduction MEIC project overview Accelerator design Ion & electron complex Interaction region Electron cooling Polarization Conclusions & Outlook Outline 3 EIC Workshop 3/17/14 JLabs fixed target program after the 12 GeV CEBAF upgrade will be world-leading for at least a decade A Medium energy Electron-Ion Collider (MEIC) at JLab will open new frontiers in nuclear science. MEIC parameters are chosen to optimize science, technology development, and project cost. We maintain a well-defined path for future upgrade to higher energies and luminosities. A design report was released on August, 2012, providing a base for performance evaluation, cost estimation, and technical risk assessment. We are working for a complete Conceptual Design Report in 2-3 years. Introduction 4 EIC Workshop 3/17/14 EIC Physics Highlights 5 Stage I+II (MEIC + EIC) Stage I (MEIC) JLab 12 GeV An EIC aims to study the sea quark and gluon-dominated matter 3D structure of nucleons and nuclei is not trivial Gluon dynamics plays a large role in proton spin Gluons in nuclei (splitting/recombining) Need polarization and good acceptance to detect spectator & fragments EIC Workshop 3/17/14 The MEIC design concept for high luminosity is based on high bunch repetition rate CW colliding beams Beam Design High repetition rate Low bunch charge Short bunch length Small emittance IR Design Small * Crab crossing Damping Synchrotron radiation Electron cooling Traditional hadrons colliders Small number of bunches Small collision frequency f Large bunch charge n 1 and n 2 Long bunch length Large beta-star KEK-B already reached above 2x10 34 /cm 2 /s Linac-Ring colliders Large beam-beam parameter for the electron beam Need to maintain high polarized electron current High energy/current ERL 6 Design Strategy for High Luminosity EIC Workshop 3/17/147 Design Strategy for High Polarization All rings have a figure-8 shape with critical advantages for both ion and electron beam Spin precessions in the left & right parts of the ring are exactly cancelled Net spin precession (spin tune) is zero, thus energy independent Spin is easily controlled and stabilized by small solenoids or other compact spin rotators Advantage 1: Ion spin preservation during acceleration Ensures spin preservation Avoids energy-dependent spin sensitivity for all species of ions Allows a high polarization for all light ion beams Advantage 2: Ease of spin manipulation Delivering desired polarization at multiple collision points Advantage 3: The only practical way to accommodate polarized deuterons ultra small g-2 Advantage 4: Strong reduction of quantum depolarization thanks to the energy independent spin tune Helps to preserve polarization of the electron beam continuously injected from CEBAF EIC Workshop 3/17/14 Energy Full coverage of center of mass energy from 15 to 65 GeV Electrons 3-12 GeV, protons GeV, ions GeV/u Ion species Polarized light ions: p, d, 3 He, and possibly Li, and polarized heavier ions Un-polarized light to heavy ions up to A above 200 (Au, Pb) At least 2 detectors Full acceptance is critical for the primary detector Luminosity Maximum luminosity >10 34 optimized to be around s=45 GeV Above cm -2 s -1 per IP in a broad CM energy range Polarization At IP: longitudinal for both beams, transverse for ions only All polarizations >70% Upgrade to higher energies and luminosity possible 20 GeV electron, 250 GeV proton, and 100 GeV/u ion Design parameters consistent with the White Paper requirements MEIC Design Parameters 8 EIC Workshop 3/17/14 MEIC Layout 9 Three compact rings: 3 to 12 GeV electron Up to 25 GeV/c proton (warm) Up to 100 GeV/c proton (cold) Warm large booster (up to 25 GeV/c) Warm 3-12 GeV electron collider ring Medium-energy IPs with horizontal beam crossing Injector 12 GeV CEBAF Pre-booster SRF linac Ion source Cold GeV/c proton collider ring Three Figure-8 rings stacked vertically Electron cooling Cross sections of tunnels for MEIC Ion Source Pre-booster Linac 12 GeV CEBAF 12 GeV 11 GeV IP MEIC collider rings Full Energy EIC Collider rings Electron cooling EIC Workshop 3/17/14 Stage I MEIC CEBAF as full-energy e - /e + injector 3-12 GeV e - /e + GeV protons 12-40 GeV/u ions Stage II EIC up to 20 GeV e - /e + up to 250 GeV protons up to 100 GeV/u ions Two independent but complementary detectors EIC at JLab 10 Pre- booster Ion linac MEIC EIC e injection IP2 IP1 Hall D Halls A-C C E B A F EIC Workshop 3/17/14 Table of Contents Executive Summary 1.Introduction 2.Nuclear Physics with MEIC 3.Baseline Design and Luminosity Concept 4.Electron Complex 5.Ion Complex 6.Electron Cooling 7.Interaction Regions 8.Outlook MEIC Design Report 11 arXiv: EIC Workshop 3/17/14 DetectorFull AcceptanceLarge Acceptance (High Luminosity) ProtonElectronProtonElectron Beam energyGeV605 5 Collision frequencyMHz750 Particles per bunch Beam CurrentA Polarization> 70%~ 80%> 70%~ 80% Energy spread10 -4 ~ 37.1~ 37.1 RMS bunch lengthcm Horizontal emittance, normalizedm rad Vertical emittance, normalizedm rad Horizontal and vertical *cm10 and 2 4 and 0.8 Vertical beam-beam tune shift Laslett tune shift0.06Very small0.06Very small Distance from IP to 1 st FF quadm7 (down) 3.5 (up) 34.5 (down) 3.5 (up) 3 Luminosity per IP, cm -2 s Nominal Design Parameters EIC Workshop 3/17/14 Survey of MEIC Design and R&D 13 MEIC systemsDesign Correction & SimulationTalk Ion source Conventional technology, Detailed simulations needed, but should not present an issue Non-linear dynamics correction started Encouraging initial simulation results Detailed work in progress V. Dudnikov Ion injector P. Ostroumov Ion pre-booster Ion large booster Ion collider ring V.S. Morozov Electron collider ring F. Lin Interaction regions V.S. Morozov, C. Weiss, P. Nadel-Turonski, Polarization simulation plannedA.M. Kondratenko, F.Lin Crab crossing New cavity design developed at ODUA. Castilla RF system R&D in progress at JLAB SRFS. Wang Electron Cooling magnetized e-source R&D 2 options (thermionic gun or RF photo- cathode gun) Ya.S. Derbenev H. Zhang D. Douglas ERL and circulator Conceptual design, e-cooling simulations done Fast kicker RF harmonic kicker concept (JLAB LDRD) Beam synch and abort TBD planned EIC Workshop 3/17/1414 Ion Sources V. Dudnikovs talk, Source-Polarimetry, Thursday MEIC ion source design parameters are within the state of the art MEIC ion sources reply on existing and mature technologies Un-polarized ion sources Electron Beam Ion Source (EBIS) Electron Cyclotron Resonance (ECR) ion source Polarized ion sources Atomic Beam Polarized Ion Source (ABPIS) for polarized light ions Proposed Universal Atomic Beam Polarized Ion Source (ABPIS) V. Dudnikov EIC Workshop 3/17/14 Pulsed linac, peak power 680 kW Consists of quarter wave and half wave resonators Originally developed at ANL as a heavy-ion driver accelerator for Rare Isotope Beam Facility Adopted for MEIC ion linac because: Satisfies MEIC ion linac requirements Covers similar energies, variety of ion species Excellent and mature design All subsystems are either commercially available or based on well-developed technologies Ion Linac 15 ParametersUnitValue Speciesp to lead Reference Design 208 Pb Kinetic energyMeV/u100 Max. pulse current Light ions (A/q3) Heavy ions (A/q3) mA Pulse repetition rateHz10 Pulse lengthms0.25 Max. beam pulsed powerkW680 Fundament frequencyMHz115 Total lengthM150 Superconducting Normal conducting QWR HWR P. Ostroumovs talk, Beam Physics, Tuesday EIC Workshop 3/17/14 Purpose of pre-booster Accumulation of ions injected from linac Acceleration of ions Extraction and transfer of ions to the large booster Design concepts Figure-8 shape (Quasi-independent) modular design FODO arcs for simplicity and ease optics corrections Design considerations Maximum bending field: 1.5 T Maximum quad field gradient: 20 T/m Momentum compaction smaller than 1/25 Maximum beta functions less than 35 m Maximum full beam size less than 2.5 cm 5m dispersion-free drifts between triplets for RF, cooling, collimation and extraction Ion Pre-booster 16 Injection Arc 1 Straight 1 Arc 3 Straight 2 Arc 2 B. Erdelyi, NIU EIC Workshop 3/17/14 Accelerates protons from 3 to 25 GeV (and ion energies with similar magnetic rigidity) Follow electron/ion collider ring footprints, housed in same tunnel Made of warm magnets and warm RF No transition energy crossing (always below t =26.65) Quadrupole based dispersion suppression Tunable to any working point Ion Large Booster 17 IP Vertical chicane to bring low energy ions to the plane of the electron ring Add electron cooling and SRF Share detector with MEIC Possible to convert the large booster to a low energy collider ring E. Nissen (CERN), T. Satogata EIC Workshop 3/17/14 Proton above transition energy t, ions may cross t 60 crossing angle between two arcs Normal FODO-cell arcs, Cold magnets